Minimum quantity lubrication (MQL) is a metal cutting lubrication process that is much more environmentally friendly than the traditional approach of flood coolant. MQL uses a small amount of air and oil to lubricate the cutting process at the interface of the cutting tool and metal, instead of using massive amounts of coolant to quench the heat from the cutting process. One side effect of MQL is that the metal chips generated when cutting are not washed away and removed as they are with flood coolant. Having the chips removed is important because re-cutting them can damage the cutting tool and reduces its useful life.
To reduce the possibility of re-cutting the chips with MQL, an Air Blow Off (ABO) is sometimes used. The ABO uses a stream of air to remove the chips instead of a stream of coolant or other liquid. For MQL, where atomized particles of lubricant are carried in an air stream, the amount of air required to remove chips is often several times more than is necessary to propel the lubricant to the part. For MQL, using too much air with the lubricant leads to a fogging of the lubricant, which is annoying to operators, undesirable for air quality, and wasteful of the lubricant. On the other hand, using too little air for the ABO is ineffective in removing chips. Thus, the MQL and ABO air stream requirements are incompatible. So the current approach is to use separate nozzles for each function. A typical MQL applicator has an MQL fluid output nozzle and a separate ABO nozzle.
While on some machine tools the separate nozzles are not an issue, on CNC machines where tool changers are active and the parts or tables may be moving, it is difficult to place external nozzles in locations that do not interfere with the machine movements, yet are still positioned appropriately to perform the lubrication and blow off functions. The invention provides a solution to the problem of using a single nozzle in an MQL system that performs both the MQL and ABO functions.